1. Field of the Invention
This invention relates to the controlling of the output shaft in a rotary actuator by a feedback means associated with a control valve which will determine the direction, position, velocity, acceleration and deceleration of the output shaft.
2. Description of Prior Art
It is well known and recognized in this art to use a proportional control servo valve for controlling the output displacement of a rotary actuator with regard to all of its motions. Many schemes employ a four-way solenoid valve or a proportional control servo valve. When a four-way valve is used, it is necessary to insert a deceleration valve in the hydraulic circuit which would prevent the vane in a rotary actuator from slamming against its mechanical stop. The proportional control servo valve, which is much more costly than a simple four-way valve, can be controlled by an electrical signal proportional to the rotary position of the shaft through an appropriate electrical feedback circuit which would slow the vane down and not allow it to slam into the stop. Also, the electrical signal could be varying in amplitude and frequency which could give velocity, acceleration, deceleration and position control to the output shaft.